Yes it's normal. Your bump will start getting bigger around 6 to 7 months. Petite ka ba? Petite kasi ako kaya di ako mukhang buntis even at 6 months pero my OB reassured me naman that we're perfectly fine kasi naggigain naman ng timbang. :)
Iba iba naman po kasi pagbubuntis, basta healthy si baby saka walang sinabing problema si ob sainyo, no need to worry.
stephanie